Automatic train control apparatus



Dec. 19, 1933. BlRD 1,939,840

AUTOMATIC TRAIN CONTROL APPARATUS Filed June 18, 1930 O F INVENTOR.

A TTORNEY.

GEORGE BIRD Patented Dec. 19, 1933 UNITED ,YSTATES PATENT OFF-ice 1,939,840 AUTOMATIC TRAIN CONTROL APPARATUS George Bird, St. Margarets, England, assignor to The Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Application June 18, 1930, Serial No. 461,969, and

in Great Britain August 8, 1929 V,

27 Claims.

vacuumbrake equipment having means whereby an application of the brakesis adapted to be automatically effected according to traffic conditions at a predetermined time after a trafi'ic condition or signal indication has been impressed on said means, and a further object resides in the provision of means operative manually for preventing an, automatic application of the brakes if operated before an application of the brakes is eifected. 7

Another and more specific object of my invention is to provide an improved control mecha nism for a vacuum brake equipment, which mechanism preferably comprises a timing reservoir normally maintained at the vacuum obtained in the brake system, said reservoir being cut into communication with the atmosphere under predetermined traffic conditions, the increased pressure thus obtained in the timing reservoir, after a predetermined interval of time, effecting the establishment of a communication whereby an application valve device is actuated to'efiect-the admission of fluid at atmospheric pressure to the brake pipe, so as to cause an application of the brakes to be efiected.

These and other objects will appear in the following more detailed description of my invention. In the accompanying drawing, the single figure is a diagrammatic view, mainly in section, of a 4o portion of a vacuum brake apparatus embodying my invention, the apparatus being shown in its normal running and release position.

The brake equipment may comprise the usual vacuum brake cylinderz (not shown), which is in communication with the brake pipe 47 within which a' vacuum is automatically maintained by the action of an ejector (-not shown), which may be of the usual type and which may be connected to the main reservoir 70. The admission of atmospheric air to the brake pipe, and'the withnet 1, which is, arranged to be automatically de energized when the traffic conditions are unfavorable to the continued progress of the train.

The electro-magnet 1 is provided with an armature 2 adapted to control the operation of two valves, 3, 4, through the medium of a plunger 5, which is attached to the armature. -With the eiectro-magnet energized, the valve 3 is maintained seated and the valve 4 unseated against the pressure of a spring 6, and with the electromagnet deenergized, the valve 3 is maintained unseated and the valve 4 seated by the pressure of the spring 6. V

With the valve 3 unseated, communication is established between a chamber 7 and a chamber 7 8 leading to a timing reservoir 9, the chamber 7 being in communication with the atmosphere through a vacuum horn 10. With the valve 4 unseated, communication is established between V thechamber 8 and a chamber 11 communicating through a passage 12 and a passageand'pipe 13 with a train control vacuum reservoir 14.

The reservoir 14 is in communicationwith the main vacuum reservoir 70 of the braking system of the train through a non-return ball valve 15 and. so long as the magnet 1 is energized the valve 3 is seated and the valve 4 is unseated, so that a vacuum is maintained in the timing reservoir 9. When however, the electro-magnet 1 is deenergized so that the valve 3 is unseated, atmospheric air is admitted to the timing reservoir 9 from the chamber 8, the entering air before passing through the valve 3 passing. through the vacuum horn 10 so as to give an audible indica- 7 tion that the electro-magnet 1 has become deenergized. V j

The timing reservoir 9 is in communication through a passage 16 with a chamber 17 formed on one side of a flexible diaphragm 18, which is subject to the pressure of a spring 19 contained in this chamber. The diaphragm is provided with a central head 20 which is pivotally connected at 21, to an intermediate point in a lever 22, one end of which is pivoted at 23 to the casing of the device, the other end of'the lever 22 being pivotally connected at 24 to one end of a link 25, the other end of which is pivotally connected at. 26 to a stem 2'7 of a valve 28hereinafter termed the timing valve. The lever 22 and link 25 constitutes the two arms of a toggle mechanism, the lower end of the link 25 connected to the valve stem '27 being also connected to one end of an expansion spring 29, the other end of which is connected to the casing'of the device. The lever 22 and link-25 forming the toggle mechanism and brake valve device 71, a pipe '72, and main resother.

the spring 29 are so arranged that the latter tends to maintain the valve stem 27 and valve 28 in one or the other of two positions corresponding to the position of the diaphragm 18, the spring 29 serving through the toggle mechanism to move thevalve stem 27 rapidly and positively from one position to the other inv response to the variations in the pressure obtaining in the timing reservoir 9.

The timing valve 28 is of the double beat type adapted when in the position illustrated to establish communication between the passage 12 leading to the train control vacuum reservoir 14 and a pipe 30 leading to the application valve mechanism, hereinafter termed the application valve pipe, while when the valve 28 is in the position opposite to that illustrated, communication is established between the application valve pipe 30 and the atmosphere through the port 31.

The application valve pipe 30 establishes communication between the apparatus above described and the application valve, which comprises a casing or body 32 divided into fourcompartments arranged vertically one above the The application valve pipe 30 leads to the uppermost or first compartment 33, which is separated from the second or next lower compartment 34 by a diaphragm 35, this compartment 33 containing a spring 36 tending to move the diaphragm downwardly. The compartment 34 is in open communication with the at mosphere through a port 37 in the wall of the casing 32 and also communicates with the third compartment 38 past a valve 39 operated by the diaphragm 35 and maintained open so long as the diaphragm is held in its uppermost position against the action of the spring .36. The compartment 38 is provided with a relief valve 40 adapted to permit the entrance of atmospheric vair to the compartment 38 when a predetermined adjustable degree of vacuum obtains therein, the relief valve being provided with .an adjustable control spring 41 for this purpose. Preferably, the relief valve 40 is so adjusted as to permit the .entrance of atmospheric air to the compartment "38 when the vacuum exceeds 10 inches. The com.-

partment 38 communicates with thefourth or lowest compartment 42 through a valve 43 operated by the diaphragm 35, which is arranged to be closed so long as the diaphragm 35 isin its uppermost position, under, which conditions, a valve 44 is open, establishing communication between the compartment 42 and a chamber 45, which is provided with a pipe 46 leading to the ejector (not shown) of the vacuum brake through the ing to the ejector pipe 46.

It will be seen that the valves 39,, 43 and 44 are all mountedv upon a common valve stem 49, the upper end of which constitutes a head 50 secured to the diaphragm 35. p

The application valve pipe 30 is connected by means of a branch pipe 51 to a vacuum switch device 52 comprising a casing 53 divided into two compartments 54, by means of '2. :dia phragm 56, the chamber 54 being subject tothe pressure in the pipe 51 and the other chamber 55 being in open communication with the atmosphere through a port 557. The diaphragm 56 arranged to actuate an electrical switch contact -58, the chamber 54 containing a spring 59 tending to move the diaphragm 56 to a position in which the switch contact 58 is opened. The switch contact 58 is included in an electric circuit forming part of an acknowledging mechanism comprising an acknowledging switch 73, which is adapted to be operated by the engineer of the train, the acknowledging switch and the Vacuum switch contact 58 being included in a circuit which when closed serves to reenergize the electro-magnet 1 of the control mechanism when this magnet has been deenergized by the train passing a signal. Also included in this circuit is a battery 74 or any other desired source of electric current.

The operation of the apparatus is as follows:

Under normal running conditions the electromagnet lot the mechanism is maintained energized, so that the valve 3 is seated and the valve 4 is unscated. As a result the timing reservoir 9 is in communication through chamber 8, and the valve 4, chamber 11 and passage 12 with the pipe 13 leading to the train control vacuum res ervoir 14 and the normal degree of vacuum is thus maintained in the timing reservoir 9. The

diaphragm 18, subject to the pressure obtaining in this reservoir, is maintained in its left hand position, the valve 28 actuated thereby being in a corresponding position in which communication between the passage 12, leading to the train control vacuum reservoir 14 and the application The vacuum is also maintained in the chamber 33 of the application valve which communicates with the application valve pipe 30, with the result that the diaphragm 35 and valve stem 49 are held in their uppermost positions against the action of the spring 36. With the stem 39 thus held, the valves 39 and 44 are maintained unseated and the valve '43 seated. With the valve 39 unseated, the second and third chambers 34 and 38 are in communication with one another and with the atmosphere through the port'37, while with the valve 43 seated, communication between the chamber 38 and the chamber 42 is cut off. With the valve '44 unseated, the ejector pipe 46 is in communication. with the vacuum brake pipe 47, the interior of-whic-h is thus maintained at the desired normal degree of vacuum.

In the event of the elect-ro-magnet 1 becoming deenergized, as for instance the train passing a signal at danger, the valve 3 controlled by this magnet is unseated and the valve 4 is seated. As a result, air enters the vacuum operated horn 10 and passing through the unseated valve 3 enters the chamber 8 and timing reservoir 9, thereby reducing the vacuum therein. The timing reservoir 9.is designed to be of such capacity that a prearranged time of, for instance, six seconds, will elapse before the timing reservoir attains atmospheric pressure and. after the expiration of this interval, the spring 19, acting upon the 1..)-

diaphragm 18, will move the latter toward the right hand, thereby reversing the position of the toggle mechanism so that the timing valve 28 is rapidly moved with a snap action into the position reverse to that illustrated. In this position, the timing valve 28 cuts off communication between the train control vacuum reservoir 14 and the application valve pipe 30 and establishes communication between the pipe 30 and the atmosphere through the port 31, with the result,

ILL:

fore this occurs, that is to say, before the exthat the chamber 33 of the application valve is filled with air at atmospheric pressure. ,The diaphragm 35 of the application valve and the valve stem 49 carried thereby are now moved downwardly under the action of the valve spring 36, seating the valves 39 and 44 and unseating the valve 43, with the result, that communication between the third chamber 38 and the second chamber 34 is cut oif by the valve 39 and communication between the chamber 38 and the vacuum brake pipe 47 is established through the chamber 42. Under the brake pipe vacuum thus established in the third chamber 38, the relief valve opens and admits atmospheric air into the chamber and brake pipe until the vacuum therein is decreased to the value for which the relief valve 40 is adjusted, for instance 10 inches of vacuum. r

The vacuum in the brake pipe is thus reduced to this extent with the result that a service application of the brakes is eifected.

It will be understood that the ,service brake application is only effected after the expiration of the interval of time determined by the timing reservoir 9 and that afterthe expiration of this interval the atmospheric pressure in the application valve pipe 30 will permit the spring 59 of the vacuum switch 52 to open the switch contact 58 with the result that the energizing circuit of the electro-magnet 1 is opened. If, however, be-

piration of the time interval above referred to, the engineer of the train closes his acknowledging switch '73 as an indication that he has observed the signal exhibited, the electro-magnet 1 will be reenergized, since the vacuum switch contact 58 has not yet been opened.

In the event of the engineer omitting to acknowledge, the signal in this manner so that an automatic application of the brakes is effected, 'the energizing circuit of the electro-magnet 1 is chamber 34 of the application valve and comprising a rotatable rod 60 secured. to an external operating. handle 61. The inner end of the rod 60 is provided with a lug or cam '62 so that by rotating the rod 60 by means of the handle 61 'the diaphragm 35 and valve 39 can be held in their upper positions, thereby rendering the automatic action inoperative.

The handle 61 of the cut-out latch is preferably sealed in its normal position and'can only be operated to place the'application valve out of action by breaking the seal.

When thevehicle or train is being operated in clear territory, the automatic control mechanism will be maintained in its f normal position as shown in the drawing, and the application and release of the brakes will be controlled in the usual manner through the medium of the ordinary brake valve device 71.

While one illustrative embodiment of the invention has been described in detail, it is not my intention to limit its scope to that embodiment or otherwise than by the terms of the appended claims.

Having now described my invention, what I.

claimasnew and desire to secure by Letters Patent, is:

tion' has been impressed on the first mentioned means, and means operative manually to pre-.

vent the operation of the first mentioned means.

2. In a vacuum brake equipment, the combination with a brake pipe normally maintained at a partial vacuum for maintaining the brakes released, of means operative automatically according to traific conditions for controlling the admission of fluid to said brake pipe to effect an application of the brakes, means for delaying the admission of fluid to the brake pipe fora predetermined period of time after the traflic condition has been impressed on the first mentioned means, means operative manually to prevent the operation of the first mentioned means when operated Within a predetermined time after the trafiic condition is impressed on the first mentioned means, and means operative to indicate .when the traflic condition is impressed on the first mentioned means.

3. In a vacuum brake equipment, the combination with a brake pipe normally maintained at a partial vacuum for maintaining the brakes released, of means operative automatically accordingto traihc conditions for controlling the admission of fluid to said brake pipe to eifect an application of the brakes, means for delaying the admission of fluid to the brake pipe for a predetermined period of time after the traifio condition 1;

has been impressed on the first mentioned means, means operative manually to prevent the operation of the first mentioned means when operated within a predetermined time after the trafficcondition is impressed on the first mentioned means, and means operative to indicate the inierval of time in which the manually operative means may be operated to efiectively prevent the operation of the first mentioned means.

4. In a vacuum brake equipment, the combination with a brake pipe normally maintained at a partial vacuum for maintaining the brakes released, of an application valve device operative to admit fluid to the brake pipe to efiect an application of the brakes and normally maintained in a position to prevent the admission of fluid to the brake pipe, a relief valve device operative to admit fluid to said application valve device, andmeans operative according to trafiic conditions for controlling the operation of said appli- 1 cation valve device. to admit fluid supplied through said relief valve to said brake pipe.

5. In a vacuum brake equipment, the combination with a brake pipe normally maintained at a partial vacuum for maintaining the brakes j' released, of an application valve normally preventing the admission of fluid to the brake pipe and operative to admit fluid to said brake pipe,

'a movable abutment normally subject on one side to atmospheric pressure and on the other side to a pressure below atmospheric pressure for maintaining said valve in its normal position and operative upon an increase in the pressure on said other side thereof to operate said valve to admit fluid to the brake pipe, a reservoir normally maintained at a partial vacuum-means subject to the'normal pressure of said reservoir and atmospheric pressure for normally establishing communication through which the pressure on said other side of the abutmentis main-- 6.. In a vacuum brake equipment, the combination with a brake pipe normally maintained at a partial vacuum for maintaining the brakes .released, of an application pipe normally maintainied at a partial vacuum, an application valve device normally subject to the normal pressure of .fluid in said application pipe and the opposing atmospheric pressure for preventing the admission of fluid to said brake pipe and operative upon an increase in the pressure of fluid in said application pipe for admitting fluid to s id brake pipe to effect an application of the f valve mechanism operative to increase the pi ssure of fluid said application pipe, and valve means controlled according to traffic conditions for controlling the operation of said valve mechanism.

:7. In a vacuum brake equipment, the combine-- tion with a brake pipe normally trained at a partial vacuum for maintaining the hrakes released, of an application pipe nori ally maintained at a partial vacuum, an application vs vs device normally subject to the normal press re of hold in said application pipe and the opposing atmospheric pressure for preventing the admi sion of fluid to said brake pipe and operative upon an increase in the pressure of fluid insaid application pipe for admitting fluid to said brake pipe to effect an application of the brakes, valve means normally establishing communication through which said application pipe is normally maintained at a partial vacuum and opera ve to close said communication and to establish another communication through which fluid is admitted to the application pipe, and magnet valve means controlled according to traffic conditions for operating said valve means.

8. In a vacuum brake equipment, the combination with a brake pipe normally main-tail ed at a partial vacuum for maintaining the brakes released, of an application pipe normally maintained at a partial vacuum, valve means normally establishing communication through which said application pipe is maintained at a partial vacuum and operative to establish another communication through. which fluid is admitted to the application pipe, an application valve device normally subject to the normal pressure of fluidin said application pipe and the opposing atmospheric pressure for preventing the admission of fluid to said brake pipe and operative upon an increase in the pressure of fluid in said application pipe for admitting fluid to said brake pipe to effect an application of the brakes, magnet valve means controlled automatically according to traffic conditions for controlling the operation of said valve means, means for delaying the operation of said valve means for a predetermined period of time after a traific condition has been impressed on said magnet valve meana and manually operative means for preventing the operation of said magnet valve means when operated within said period of time.

9. In "a vacuum brake equipment, the combiner tion with a brake pipe normally maintained at a partial vacuum for main-taming the brakes released, of an application pipe normally maintained at a partial vacuum, an application valve device normally subject to the normal pressure of fluid in said application pipe and the opposing atmospheric pressure tor preventing the admission of fluid to said brake pipe and operative upon an increase the pressure of fluid in said application pipe for admitting iluid to said brake pipe to effect an application of the brakes, valve means normally -=establish ing communication through which said application pipe is maintainedat a partial "vacuum and operative to es tablish another communication through which fluid is admitted to the application pipe, electrical valve means controlled automatically according to the traffic conditions for controlling the operation of said valve means, means for delaying the operation of said valve means for a predetermined period of time after a traffic condition has been impressed onsaid electrical valve means, manually operative means for preventing the operation of said electrical valve means when operated Within said period of time, and means operative automatically upon the operation of said valve means to admit "flu-id to the brake pipe for rendering said manually operative means inelrect ive to prevent an application of the brakes.

10. In a vacuum brake equipment, the comlei-nation with a brake pipe normally maintained at a partial vacuum 'for maintaining the brakes released, of an -applioation pipe normally maintained at a partial "vacuum, an application va'lve device normally subject to the normal pressure of fluid in said application pipe and the opposing atmospheric pressure for preventing the -admission of fluid to said brake pipe and operative upon an increase in the pressure-of fluid in said application pipe for admitting fluid to said brake pipe to effect an application of the brakes, valve means normally establishing communication through which said application pipe is maintained at a partial vacuum and operative to establish another communication through which fluid is admitted to theapplication pipe, electrical means controlled automatically according to the traffic conditions for operating said valve means, means for delaying the operation of said valve means fora predetermined period of'time after a trafficcondition has been impressed on said electrical means, manually operative means for preventing the operation of said valve means when operated Within said period of time, and means operative upon an increase in the pressure of fluid in said application pipefor rendering said manually operative means ineffective to prevent an application of the brakes.

11. In a vacuum brake equipment, the combination with a brake pipe normally maintained at a partial vacuum for maintaining the brakes released, a-reservoir maintained at a partial vacuum, a timing reservoir, electrical means normal- 1y energized and establishing communication from the first mentioned reservoir to said timing reservoir 'for normally maintaining said timing reservoir at a partial vacuum, said electrical means being deenergized and operative according to traflic conditions for closing said communication and establishing another communication through which fund is admitted to said timing reservoir, an application valve device having .a

vacuum chamber normally connected to the first mentioned reservoir and maintained at a partial vacuum, valve 'means normally maintaining communication open from the first men tioned reservoir to said vacuum chamber and. operative upon'an increase in the pressure of fluid in said timing reservoir for admitting fluid to said vacuum chamber,- and means included in said application valve device operative upon an increase in the pressure of fluid in said chamber for admitting fluid to said brake pipe to effect an application of the brakes.

12. In a vacuum brake equipment, the combination with a brake pipe normally maintained at a partial vacuum for maintaining the brakes released, a reservoir maintained at a partial vacuum, a timing reservoir, electrical means normally energized and establishing communication from the first mentioned reservoir to said timing resrvoir for normally maintaining said timing reservoir at a partial vacuum, said electrical means being deenergized and operative according to traflic'conditions for closing said communication and establishing another communication through which fluid is admitted to said timing reservoir, an application valve device having a vacuum chamber normally connected to the first mentioned reservoir and maintained at a partial vacuum, valve means normally maintaining communication open from the first mentioned reservoir to said vacuum chamber and operative upon an increase in the pressure of fluid in said timing reservoir for admitting fluid to said vacuum chamber, means'included in said application valve device opreative upon an increase in the pressure of fluid in said chamber for admits ting fluid to said brake pipe. to effect an application of the brakes, andmanually operative means for controlling thefenergization of said electrical means when operated before said valve means are caused to operate .to'admit fluid to said'vacuum chamber.

13.. In aivacuurn brake equipment, thecombination with a brake pipe normally maintained at a partial vacuum for maintaining the brakes released, a reservoir maintained at a partial vacuum, a timing reservoir, electrical means normally energized and establishing communication from the first mentioned reservoir'to said timing reservoir for normally maintaining said timing reservoir at a partial vacuum, said electrical means being deenergized and operative according to traffic conditions for closing-said communication and establishing. another communication through which fluid is admitted to said timing reservoir, an application valve device having a vacuum chamber normallygconnected to the first mentioned reservoir and maintained at a partial vacuum, valve means normally maintaining communication openirom thefirst mentioned reservoir to said vacuum chamber and operative upon an increase in the pressure of fluid in said timing reservoir for admitting fluid to said vacuum chamber, means included in said application valve device operative upon, an increase inthe pressure of fluidin said chamber for admitting fluidto said brake. pipe to eifect an application of the brakes, manually operative means for controlling the ,ene'rgization of said electrical means when operated before said valve means are causedto operate to admit fluid to said vacuum chamber, and means operative automatically upon the operation of said valve means to admit fluid to .said vacuum chamber for rendering said manually operative means ineffective to control the "energization of said electrical means.

14. In a vacuum brake equipment, the combination with a brake pipe normally maintained at a partial vacuum for maintaining the brakes released, of an application valve device operative to admit fluid to the brake pipe to eiTect an application of the brakes and normally maintained in a position to prevent the admission of fluid to the brake pipe, means operative according to traflic conditions for controlling the operation of said application valve device to admit fluid to said brake pipe, and means included in said application valve device operative to lock the application valve device against operation 1 to admit fluid to the brake pipe.

15. In a vacuum brake equipment, the combination with a brake pipe normally maintained at a partial vacuum for maintaining the brakes released, of an application valve device operative to admit fluid to the brake pipe to eifect an application of the brakes and normally maintained in a position to prevent the admission of fluid to the brake pipe, means operative according to traflic conditions for controlling the operation of said application valve device to admit fluid to said brake pipe, and manually operative means for locking said application valve device against operation from its normal position.

16. In avacuum brake equipment, the combination with a source of partial vacuum and a brake pipe normally maintained at a partial vacuum for maintaining the brakes released, of a valve device operative to admit fluid to the brake pipe to'effect an application of the brakes and normally maintained in a position to, establish a communication from the source of partial vacuum to the brake pipe and to prevent the admissionof fluid to the brake pipe, valve mechanism operative to control the operation of said valve device, and valve means operative according to trafiic conditions for controlling the operation of said valve mechanism.

17. In a vacuum brake equipment, the combination with a source of partial vacuum and a brake pipe normally maintained at a partial vacuum for maintaining the brakes released, of a valve device operative to admit fluid to the brake pipe to effect an application of the brakes and normally maintained in a position to establish a communication from the source of partial vacuum to the brake pipe and to prevent the admission of fluid to thebrake pipe, a reservoir normally maintained at a sub-atmospheric pressure, valve mechanism subject to variations in the pressure of fluid in said reservoir for controlling the operation of said valve device, and

valve means operative according to traffic conditions for varying the pressure of fluid in said reservoir.

18. In a vacuum brake equipment, the combination with a source of partial vacuum and a brake pipe normally maintained at a partial vacuum for maintaining the brakes released, oi. a; valve. device operativeto admit fluid to the brake pipe to effect an application of the brakes and normally'maintained in a position toaestablish'a communication from the source of partial vacuumto the brake pipe and to prevent the admission of fluid to the brake pipe, a reservoir normally maintained at a sub-atmospheric pressure, valve mechanism normallysubject to the pressure of fluid in said reservoir for maintaining said valve device in its normal position and operative upon an increase in the pressure of fluidin said reservoir for causing said valve. device .to

operate to admit fluid to the brake pipe, and

means operative according to traflic conditions for controlling the admission of fluid to said reservoir.

"19. In a vacuum brake equipment, the combination with a source of partial vacuum and a brake pipe normally maintained at a partial vacuum for maintaining the brakes released, of a valve device operative to admit fluid to the brake pipe to effect an application of the brakes and normally maintained in a position to establisha communication from the source of partial vacuum to the brake pipe and to prevent the admission of fluid to the brake pipe, a reservoir normally maintained at a sub-atmospheric pressure, valve mechanism normally subject to the pressure of fluid in said rmervoir for maintaining said valve device in its normal position and operative upon'a predetermined increase in the pres- :sure 01 fluid in said reservoir for controlling the operation of said valve device to admit fluid to the brake pipe, and means operative in accordance with traihc conditions for controlling the pressure of fluid in said reservoir.

20. In a vacuum brake equipment, the combination with a source of partial vacuum and a brake pipe normally maintained at a partial vacuum for maintaining the brakes released, of a valve device operative to admit fluid to the brake pipe to effect an application of the brakes and normally maintained in a position to establish a, communication between the source of partial vacuum and the brake pipe and to prevent the admission of fluid to the brake pipe, a. reservoir normally maintained at a sub-atmospheric pressure, valve mechanism normally subject to the pressure of fluid in said reservoir for maintaining said valve device in its normal position and operafive upona predetermined increase in the pressure of fluid in said reservoir for controlling the operation of said valve device to admit fluid to the brake pipe, and valve means operative in accordance with traflic conditions for admitting fluid to said reservoir.

21. In a vacuum brake equipment, the combination with a brake pipe normally maintained at a partial vacuum for maintaining the brakes released, ot a valve device operative to admit fluid to the brake pipe to efiect an application of the brakes and normally maintained in a position to prevent the admission of fluid to the brake pipe, a reservoir normally maintained at a sub-atmospheric pressure, valve mechanism normally subject to the pressure of fluid in said reservoir for maintaining said valve device in the position to prevent the admission of fluid to the brake pipe and operative upon a predetermined increase in the pressure of fluid in said reservoir for controlling the operation of said valve device to admit fluid to the brake pipe, magnet valve means operative in accordance with traific conditions for admitting fluid to said reservoir, and means under manual control adapted, when operated before said predetermined pressure is obtained in said reservoir,

to control the operation of said magnet valve means to close off the flow of fluid to said reservoir. i

22. In a vacuum brake equipment, the combination with a brake pipe normally maintained at a 'partial vacuum for maintaining the brakes released, of a valve device operative to admit fluid to the brake pipe to effect an application of the brakes and normally maintained in a position to prevent the admission of fluid to the brake pipe, a reservoir normally maintained at a sub-atmospheric pressure, valve mechanism normally subject to the'pressure of fluid in said reservoir for maintaining said valve device'in the position to prevent the admission of fluid to the brake pipe and operative upon a predetermined increase in the pressure of fluid in said reservoir for controlling theoperation of said valve device to admit jfluid to the brake pipe, magnet valve means operative in accordance with traflic conditions for admitting fluid to said reservoir, and means under manual control adapted, when operated Within a predetermined period of time, after said magnet valve means operates to'admit fluid to said reservoir to control the operation of the magnet valve means to close off the flow of fluid to said reservoir and thereby prevent said predetermined pressure from being obtained in said reservoir.

23. In a vacuum brake equipment, the combination with a brake pipe normally maintained at a partial vacuum for maintaining the brakes released, of a'valve device operative to admit fluid to the brake pipe to effect an application of the brakes and normally maintained in a position to prevent the admission of fluid to the brake pipe, a reservoir normally maintained at a subatmospheric pressure, valve mechanism normally subject to the pressure of fluid in said reservoir for maintaining said valve device in the position to prevent the admission of fluid to the brake pipe and operative upon a predetermined increase in the pressure ofv fluid inJsaid reservoir for controlling the operation of said valve device to admit fluid to the brake pipe, magnet valve means operative in accordance with traflic conditions for admitting fluid to said reservoir, manually controlled means adapted, when operated within a predetermined period of time after said magnet valve means operates to admit fluid to said reservoir, to con'trolihe operation of the magnet valve means'to close oif'the flow of fluid to said reservoir and thereby prevent said predetermined pressure from being obtained in said reservoir, and means operated automatically for rendering the manually controlled. means ineffective to control the operation of the magnet valve means when the manually controlled means is operated alter predetermined period or time has elapsed.

24QIn a vacuum brake equipment, the combination with a'hrake pipe normally maintained at a partial vacuum 101' maintaining the brakes released, of. a valve device operative to admit fluidto the brake pipe to eflect an application of the brakes and normally maintained in a position to prevent the admission oi. fluid to the brake pipe,'a reservoir normally maintained at a subatmospheric pressure, valve mechanism normally subject to the pressure or fluid in said reservoir for maintaining said valve device in the position to prevent the admission or fluid to the brake pipe and operative upon a predetermined increase in the pressure of fluid in said reservoir for controlling the operation or said valve device to admit 1111111 to the brakepipe, magnet valve means operative in accordance with traflic conditions for admitting fluid to said reservoir, manually controlled means adapted, when operated within a predetermined periodof time after said magnet valve means operates to admit fluid to said reservoir, to control the operation of the magnet valve means to close or! the flow or fluid to said reservoir and thereby prevent said predetermined pressure from being obtained in said reservoir, means. operated automatically for rendering the manually controlled means ineffective to control the operation or the magnet'valve means when the manually controlled means is operated after said predetermined period of time has elapsed, and means operative to indicate to an operator the period of time in which said manually controlled means may be operated to effect the operation of said magnet valve means.

25. In a vacuum brake equipment, the combination with a brake pipe normally maintained. at a partial vacuum for maintaining the brakes released, of a valve device operative to admit fluid to the brake pipe to effect an application of the brakes and normally maintained in a position to prevent the admission of fluid to the brake pipe, a reservoir normally maintained at a sub-atmospheric pressure, valve mechanism normally subject to the pressure of fluid in said reservoir for maintaining said valve device in the position to prevent the admission of fluid to the brake pipe and operative upon a predetermined increase in the pressure of fluid in said reservoir for controlling the operation of said valve device to admit fluid to the brake pipe, magnet valve means operative in accordance with trafiic conditions for admitting fluid to said reservoir, manually controlled means adapted, when operated within a predetermined period of time after said magnet valve means operates to admit fluid to said reservoir, to control the operation'of the magnet valve means to close off the flow of fluid to said reservoir and thereby prevent said predetermined pressure from being obtained in said reservoir, means operated automatically for rendering the manually controlled means ineffective to control the operation of the magnet valve means when the manually controlled means is operated after said predetermined period of time has elapsed, and means operated by fluid flowing to said reservoir for indicating to an op erator the period of time in which said manually controlled means is effective to control the opera-- tion of said magnet valve means.

26. In a vacuum brake equipment, the combination with a brake pipe normally maintained at a partial vacuum for maintaining the brakes released, of a valve device operative to admit fluid to the brake pipe to effect an application of the brakes and normally maintained in a position to prevent the admission of fluid to the brake pipe, a reservoir normally maintained at a subatmospheric pressure, valve mechanism normally subject to the pressure of fluid in said reservoir for maintaining said valve device in the position to prevent the admission of fluid to the brake pipe and operative upon a predetermined increase in the pressure of fluid in said reservoir for controlling the operation of said valve device to admit fluid to the brake pipe, magnet valve means operative in accordance with traffic conditions for admitting fluid to said reservoir, manually controlled means adapted, when operated within a predetermined period of time after said magnet valve means operates to admit fluid to said reservoir, to control the operation of the magnet valve means to close oil the flow of fluid to said reservoir and thereby prevent said predetermined pressure from being obtained in said reservoir, means operated automatically for rendering the manually controlled means ineffective to control the operation of the magnet valve means when the manually controlled means is operated after said predetermined period of time has elapsed, and means operated by fluid flowing to said reservoir for audibly indicating to an operator the period of time in which said manually controlled means is effective to control the operation of said magnet valve means.

1 27. In a vacuum brake equipment, the combination with a reservoir maintained at a subatmospheric pressure and a brake pipe normally maintained at a sub-atmospheric pressure for maintaining the brakes released, a valve device normally subject to the opposing pressures of the atmosphere and reservoir for establishing a communication between the reservoir and brake pipe to maintain the brake pipe at sub-atmospheric pressure, and operative upon an increase in the sub-atmospheric pressure for closing said communication and for establishing another communication through which fluid at atmospheric pressure is admitted to the brake pipe to effect an application of the brakes, valve mechanism operative to close communication from the reservoir to the valve device and to establish a communication through which fluid at atmospheric pressure is admitted to the valve device to increase the sub-atmospheric pressure therein, and valve means operative according to traflic conditions for controlling the operation of said valve mechanism.

GEORGE BIRD. 

